Carriage and platen control for typewriters



Aug. 18, 1959 v H. L. THOLSTRUP 2,900,065

CARRIAGE AND PLATEN CONTROL FOR TYPEWRITERS Filed Oct. 4, 1956 e Sheets-Sheet 1 IN V EN TOR.

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CARRIAGE AND PLATEN CONTROL FOR TYPEWRITERS Filed 001;. 4, 1956 6 Sheets-Sheet 6 IN VEN TOR. f/i/v/zv Z. 7/ /0L57RUP A Tram/5y United States PatentO CARRIAGE AND PLATEN CONTROL FOR TYPEWRITERS Henry L. Tholstrup, Rochester, N.Y., assignor to Commercial Controls Corporation, Rochester, N.Y., a corporation of Delaware Application October 4, 1956, Serial No. 613,900

Claims. (Cl. 197-73) This invention relates to power operated typewriters and printers and more particularly to carriage and platen control mechanism for such machines.

'In some printers, such as that in my concurrently filed application Serial No. 613,877, entitled Carriage Control Mechanism for Power Driven Printer, the power connection between the drive mechanism and the type levers is such that the type levers cannot be shifted by shifting the type basket between upper and lowercase positions.

It is, therefore, necessary to provide a control mechanism for the carriage and platen structures which permit the shifting of the platen between upper and lowercase printing positions.

It is, therefore, the principal object of this invention to provide a carriage and platen control mechanism for typewriters wherein the platen may be shifted between upper and lowercase positions in reference to a fixed type irnpact oint;

p It is a further object of the invention to provide power means for shifting the platen into both uppercase and lowercase positions. v y

it is a still further object of the invention to provide a power transmission system by which the platen may be shifted between upper and lowercase printing positions with certainty without regard to the transverse position of the carriage.

These and other objects and advantages of the invention will become apparent from a reading of the following specification in reference to the drawings which form a part of this application, and in which drawings:

Fig. 1 is a side elevational view of a carriage mechanism in association with a power operated printer;

Fig. 2 is a horizontal view through the base of the carriage, taken on line 2-2 of Fig. 1, partsrbeing broken away to show underlying structure; I

Fig. 3A is a vertical sectional view through the carriage of the printer, looking from the left and illustrating platen support and shifting mechanism at the right end of the carriage while the platen is in lowercase printing position; Y I e I -Fig. 3B is a vertical sectional View on the same plane as that illustrated in Fig. 3A, Fig. 3B illustrating power transmitting mechanism in the base of the printer, and Figsp3A and 3B together-constituting acontinuation of the" related mechanism at theright side of the printer;

Fig. 4 is a view on the same plane as Fig. 3A, showing, however, the platen shifted into uppercase position;'

Fig. Sis a view taken on line 55 of Fig. 4;

Fig. 6is a'view taken on line 66 of Fig. 4.

Fig. 7 is a fragmentary view of' certainof the power transmitting mechanism shown in Fig. 33, showing, howdescription that is to follow.

Fig. 11 is a diagrammatic representation of the platen control mechanism.

A positive drive connection for the type levers requires that the type basket be fixed in relation to the power transmitting system. Therefore, resort must be had to a system for printing upper and lowercase characters which is compatible with a fixed type basket. In printers of the conventional typewriter category, the type basket is disposed in an upper position for the typing of lowercase characters and is depressed to a lower position for the printing of uppercase characters. This arrangement, however, is not suitable in a machine having a fixed type basket; therefore, mechanism is provided herein whereby the platen may be shifted upwardly for the typingof uppercase characters and returned to a lower position for the typing of lowercase characters. One form of mechanism for accomplishing these operations is illustrated in the drawings, and reference thereto will now be had in the A carriage 10 constitutes the vehicle for a platen 12 and a paper roll holder 14. The carriage consists essentially of a base plate 16 (Fig. 2) having a pair of upstanding end walls 18 and 20. Fixed in the end walls 18' adapted to receive and slide on the bearing rods 22 and 26, respectively, and a pair of shorter bearing sleeves 36,.

which are adapted to receive and slide on the bearing rods 24 and 28, respectively.

It will be seen, therefore, that the carriage truck 32 constitutes the connection between the carriage 10 andv the base frame 30 of the printer. As shown in Fig. 1, an

escapement rack 38 is fixed to the bottom of the carriage frame and thereby controls the movement of the carriage transverse of the printer frame 30. Movement of the carriage truck 32 is controlled by a pair of stabilizing tapes.

40 and 42 which are effective to limit the transverse movement of the carriage truck 32 to one-half the distance traversed by the carriage 10. The stabilizing tape 40 is trained about a pulley 44 attached to and extending lat-'- erally from one face of the carriage truck 32, one end of the tape 40 being attached to an anchor 46 fixed to the inner face of the printer frame 30 at one side thereof, and the other end of the tape being fixed to the same,

side of the printer by an anchor 48 located at the inner face of the end plate 20. -In like manner, the tape 42 is trained about a pulley 50 fixed to and extending from the opposite face of the carriage truck 32, while its respective ends are also anchored to the opposite wall of the typewriter frame 30 by means of an anchor 52 and to the inner face of the end plate 18 by means of an anchor ever, the illustrated parts in the position occupied during I Fig. 9 isa vertical sectional view on line- 9-9 of Fig.

54;} From the foregoing description, it will be seen that as the carriage is reciprocated in respect to the printer frame, the carriage truck 32 will slide in the same direction on the guide rails 22-28, but this movement will be limited by the tapes to half the distance of carriage travel.

The platen 12 is supported for rotationin a pair of identical platen support plates disposed respectively adjacent the end walls 18 and 20 of the carriage on which end walls the respective plates are mounted for oblique movement in an up and down path, whereby the platen can be shifted between upper and'lowercase printing positions. Since the platen support plates are identical, their form and mounting may be observed by reference to, Figs. 4-6, wherein is illustrated a platen support plate -56-which is associated-With the carriage end wall 18at the right of the printer. The platen support plates are mounted by' means of reciprocating guide structures, one of which is shown in Fig. 5. In Fig. 4, for example, the platen support plate 56 has attached thereto a pair of brackets 58 and 60 in each of which is fixed a depending guide pin as, for example, a guide pin 62 associated with the bracket 60. These guide pins are adapted to slide in guide bearings 64 and 64a which are mounted in the end wall 18 of the carriage. By means of a pair of such guide structures associated with each of the platen support plates, these plates are mounted for movement such that the platen 12 can be raised for the typing of uppercase characters, as shown in Fig. 4, or lowered for the printing of lowercase characters, as shown in Fig; 3A.

The platen supporting plates are operated into their respective upper and lower positions by means of a linkage system, of which that associated with the platen sup porting plate 56, is shown'in Figs. 3A and 3B. Iournalled in the side plate of the carriage 10, for example, is a lever 66 which is capable of rocking about a mounting pin 68. The lever 66 and the platen supporting plate 56 are operatively connected with each other by means of a link 70 which has one end thereof pivoted to the platen supporting plate 56 by means of a stud 72 while the other end thereof is pivoted to the lever 66 by means of a pin 74, which is located slightly above and in front of the pivot 68 about which the lever 66 moves. This constitutes the lever 66 and the link 70, an eccentric device which is adapted to exert an operating force on the platen support plate 56 which is generally parallel to the axis of the guide pins 62.

The lever 66 is connected to an actuating plate 76 by means of a link 78. The actuating plate 76lis keyed to an upper shift-shaft 80 which extends between the end plates of the carriage and is journalled therein for rocking movement. By reference to Fig. 4, it will be seen that when the shaft 80 is rotated in a clockwise direction, the actuating plate 76 will pull thelink 78 in a downward direction, thereby rocking the lever 66 in a counterclockwise direction. This effectively elevates the platen supporting plate 56 to the position illustrated in Fig. 4 where the platen 12 is positioned for uppercase printing. This is the position of the parts illustrated in Fig. 11 which is a diagrammatic presentation of the mechanism involved for shifting the platen from one position to another.

By reference to Fig. 11, it will be seen that the opposite end of the upper shift-shaft 80 has also keyed thereto an operating plate 82 which serves the same function as the operating plate 76 but which has a configuration somewhat different by reason of the fact that while the plate 76 moves in one direction, the plate 82 must produce a motion which is effective in the opposite direction.

The operation plates 76 and 82, and consequently the upper shift-shaft 80, are alternately moved from one position to another by means of a pair of shift tapes 84 and. 86 interconnecting the operating plates 76 and 82,

respectively, with an intermediate shift-shaft 88 located in the base of the printer. The intermediate shift-shaft 88 extends transversely of the printer base and has it's ends journalled in the side walls of the base, so that the shaft may be rocked from one position to another by mechanism shown in Figs. 3B, 7 and 8. in these figures, the intermediate shift-shaft 88 carries at each end generally similar mechanism for imparting rocking motion to the shaft. The mechanism shown in the figures referred to is that located at the right side of the printer out in reference to the diagrammatic view of Fig. ll; it

being pointed out here that the mechanism at the left 4 side of the printer is that which controls the rocking of the shaft 88 for shifting theplaten mechanism into its uppercase printing position.

A bell crank shaft 90 has mounted at opposite ends thereof platen shift bell cranks 92 which are identical. The lowercase shift bellcrank, of Fig. 3B will serve to disclose the structure.

These. bell cranks are designed. to transmit operating power to the shift mechanism by means of an interconnecting link, such as a link 94 associated with the lowercase bell crank 9 of Fig; 3B. The shift bell cranks are operated from a power shaft 96, -as fully described in my aforesaid concurrently filed application for patent entitled Carriage- Control Mechanism for Power Driven Printer, and such operation is under control of shift magnets, in all respects the same as more fully described in said application.

Briefly: a bell crank 92 is rocked about a bell crank shaft 90 by means of a drive plate 98 fixed for rotation with the power shaft 96'. Extending from one face of the drive plate 98 are a pair of. drive pins 100 and 102. These drive pins are adapted to cooperate with elements of the bell crank 92 to drive the bell crank through its operative stroke. By reference to Fig. 3B, it may be seen that the bell crank 92 carries a bell crank latch 104, a guide plate 106, a stop pawl 108 and a pair of lugs 110 and 112. The bell crank latch 104 is pivoted on. the bell crank 92 by means of a pivot pin 114. The bell crank latch 104 is biased about the pivot pin 114 in a clockwise direction (as viewed in Fig. 3B) by means of a spring 116 which extends between the free end of the bell crank latch 104 and the bell crank 92. The bell crank latch 104 is normally held in retracted position by a bell crank trip lever 118. The bell crank trip lever 118 is pivoted on a trip lever shaft 120 about which it is normally biased in a clockwise direction (as viewed in Fig. 3B) by a spring 122 connecting the upper end of the bell crank trip lever 118 with a casing 124 in which the bell crank assembly is located. The bell crank trip lever 118 is generally L-shaped and has an inwardly extending leg.126, which at its free end has a downwardly extending finger 128, adapted to engage a latch point at the lower end of the bell crank latch 104. While the finger 128 and the latch 130 are engaged, as shown in Fig. 3B, the bell crank latch 104 will be in its retracted position against the tension of the spring 116. The power shaft 96 is constantly rotated by a suitable electric motor and, therefore, the drive plate 98 also rotates constantly. So long as the bell crank latch 104 is in its retracted position, the pins 100 and 102 of the associated drive plate 98 will rotate freely in respect to the bell crank 92. In this connection, it should be noted that the pins 100 and 102 extend into proximity with the face of the bell crank 92 such that if the bell crank latch 104 is released, its lower free end 130 will be engaged by either of the pins 100 or 102 with the result that the bell crank 92 will be driven in a clockwise direction (as viewed in Fig. 3B) about the bell crank shaft 90. 7

As the drive pin 102 (for example) is rotated in a clockwise direction, its contact with the free end of the bell crank 104 will result in a clockwise movement of the bell crank 92 about the bell crankshaft 90. This movement will continue until the slot formed between lug 112 and the end of the guide plate 106 coincides with the path of the drive pin 102. At this moment, the drive pin 102 will enter the slot and pass freely to the point where it contacts the lug 110. When the lug 110 is engaged by the drive pin 102, the segment 92 will be rocked back to its original position.

When the shift segment 92 is operated, the link 94 will transmit powerto a link 132- which is mounted for-free rotation on the intermediate shift-shaft 88. Associated. with the link 132 is a mechanism which'iskeyed to the intermediate shiftashaft .88 and which is adapted to rotate the intermediate shift-shaft 88 when operated by the link i 132. This mechanism is, in effect, a flanged sleeve 134 (Fig. 8) which is keyed to the intermediate shift-shaft 88 by means of a pin 136. The sleeve 134 has a pair of flanges projecting therefrom. A flange 138 is located in proximity to the link 132 and has a stud 140 projecting inwardly from the face thereof. The stud 140 lies in the vertical plane of the link 132 and is adapted to register with a notch 142 (see Fig. 3B) which is formed in the upper edge of the link 132. When the shift mechanism is in the uppercase position, the disposition of the ele: ments just referred to is such that the stud 140'rests in the notch 142 so that when the link 132 is pulled forward by operation of the shift segment 92, the sleeve 134 and consequently the intermediate shift-shaft 88 will be rocked in a counterclockwise direction which is effective to lower the platen supporting mechanism into lowercase printing position. I

When the intermediate shift-shaft 88 is rockedto it clockwise position, the shift tape 84 which is attached to a pin 144, carried by a flange 146 at the opposite end of the sleeve 134, will be pulled down with the result that the actuating plate 76 of Fig. 3A will be rotated in a clockwise direction, thus rotating the shift-shaft 80 in a clockwise direction to effect elevation of the platen support plates into uppercase printing position. When the shift segment 92 is operated, the link 94 will be pulled forwardly with the result that the link 132 will engage the stud 40, if the stud is in its lower position at this time, thereby rocking the intermediate shift-shaft 88 in a counterclockwise direction. This, in effect, relieves the tension on the shift tape 84 and applies tension to the shift tape 86, as seen in Fig. 11. Tension of the shift tape 86 will rotate the plate 82 and consequently the upper shift-shaft 80 in a counterclockwise direction. The result of this is that the platen support plates are lowered into lowercase printing position.

The shift segment and associated mechanism for operating the intermediate shift-shaft 88 in a clockwise direction is in all respects the same as that described in connection with the lowercase shift mechanism with the exception that a link 148 of Fig. 11, which is the counterpart of the link 132 of Figs. 3B, 7 and 8 is oppositely mounted on the intermediate shift-shaft 88 and the link, corresponding to the link 94, connecting it to the uppercase shift segment is extended to the front of the intermediate shift-shaft 88 such that the link 148 is pulled about the intermediate shift-shaft 88 in a clockwise direction.

- The fact that the shift tapes 84 and 86 each has an end thereof connected to a point in the base of the printer which is fixed in the horizontal direction and the other ends thereof connected to points in the carriage, which is movable in a horizontal direction, demands mechanism for keeping these tapes under constant tension at all times. The mechanism for the stated purpose is shown in the diagrammatic representation of Fig. 11 and the detailed nature thereof is more particularly illustrated in Figs. 9 and 10. In Fig. 11, it will be seen that the tension of the tape 84 is controlled by a pentagraph lever 150 while the tension of the tape 86 is controlled by an identical lever 152. As the carriage moves from right to left, for example, tension on the tape 86 tends to increase while tension on the tape 84 tends to decrease. Compensation of this condition is provided by the relative shortening of the pentagraph lever 152 and the relative elongation of the pentagraph lever 150. A consideration of these functions will become clear by reference to Fig. 10 which shows the details of the lever 150.

The lever 150, which is typical of both such levers employed, comprises a long arm 154, which is pivoted on the base 30 of the printer and a short curved arm 156, which is pivoted to the free end of the long arm 154. The end of the short arm 156, which is distant from its connection to the long arm 154, is pivoted to the underside of the carriage 10 by means of a pivot pin 158. The

pivot pin 158 also supports a guide pulley 160 directly under the adjacent end of the short arm 156. There is also a guide pulley 162 on a pin 164 which connects the arms 154 and 156. A pin 166 by means of which the arm 154 is mounted on the base 30 also supports a guide pulley 168. The shift tape 84 is trained upwardly from the pin 144 (Fig. 3B) about a series of guide pulleys including the pulleys 160, 162, 168 and 170. This shift tape also passes about a guide pulley 172 mounted on a pin 174 extending downwardly from the base 16 of the carriage 10. Beyond this point, the shift tape 84: is connected to the operating plate 76 as shown in Figs. 3A and 11.

j The full line position of the parts shown in Fig. 10 is that which prevails when the carriage is in its so-called home position, i.e., when it is in registration with the base. In order to initiate a typing operation, the carriage will first be shifted to the right and as the printing of a line proceeds, the parts move progressively to the left and will assume the dotted line position of Fig. 10 by the time the carriage approaches its left hand position. A study of Fig. 10 will indicate that as the arms 154 and 156 rotate about their respective pivot points 166 and 158 into the dotted line position, the short arm 156 will assume an extended position. in respect to the long arm 154 and thereby maintain shift tape tension to compensate for change of carriage position.

What is claimed is:

1. In a power operated typewriter, a stationary base structure, a carriage mounted for transverse reciprocating movement on said base structure, a platen support mounted on said carriage for movement therewith, platen support shifting mechanism also mounted on said carriage for imparting to said platen support generally vertical movement between upper and lower case printing positions, a case shift key in said base structure, laterally fixed case shift mechanism in said base structure under control of said caseshift key, a pair of flexible power transmitting tapes having one end thereof attached to said case shift mechanism and the opposite ends thereof to said platen support shifting mechanism for shifting said platen support between upper and lower case printing position, and means for maintaining a uniform amount of tension on said tapes as said carriage reciprocates transversely of said base structure.

2. In a power operated typewriter, a stationary base structure, a carriage mounted for transverse reciprocating movement on said base structure, a platen support mounted on said carriage for generally vertical movement between upper and lowercase printing positions, a case shift key in said base structure, case shift mechanism in said base structure under control of said case shift key, a flexible power transmitting tape interconnecting said case shift mechanism and said platen support, a two part pivoted lever having one end pivoted on said base structure and the other end thereof pivoted on said carriage, and means for maintaining said tape in contact with the parts of said lever for maintaining a uniform amount of tension on said power transmitting tape as said carriage reciprocates transversely of said base structure.

3. In a power operated typewriter, a stationary base structure, a carriage mounted for transverse reciprocating movement on said base structure, a platen support mounted on said carriage for generally vertical movement between upper and lowercase printing positions, a pair of case shift keys in said base structure, a pair of case shift mechanisms in said base structure respectively under control of said case shift keys, a shift-shaft mounted in said base for oscillation about its axis, a connection between one of said case shift mechanisms and said shaft for oscillating said shaft in one direction, a connection be tween the other of said case shift mechanisms and said shaft for oscillating said shaft in the other direction, a pair of flexible power transmitting means interconnecting said case shift-shaft and said platen support for respec '7 tively' transmitting motion thereto in opposite directions, and means for maintaining a uniform amount of-tension on said flexible power transmitting-means as said carriage reciprocates transversely of said base structure.

4. -In a power operated typewriter, a stationary base structure,- a carriage mounted for transverse recipro cating movement on saidbasestructure, a platen support mounted on said carriage for generally vertical movement between upper andlowercase printing positions, a pair ofcase shift keys in said base structure, a pair of case shift mechanisms in said base structure respectively under control: of said case shift'keysaishift-shaft mounted-in said base for oscillation about its axis, a connection between one of said -caseshift mechanisms and said-shaft for oscillating said shaft in'one direction, -a connection between the other of said case shift mechanisms andsaid shaft1for oscillating said shaft in the other direction, a pair of flexible power transmitting tapes interconnecting said case shift-shaft and-said platen support for respectively transmitting motion thereto in opposite directions, and means for maintaining a uniform amount of tension on said tapestas said carriage reciprocates transversely of said base structure.

5. :In a power operatedtypewriter, a stationary base structure, a carriage'mounted for transversereciprocating movement onsaid base structure, a platen support mounted on said carriage for. generallyvertical movement 8 i between upper and'lowercase printing positions, a pair of case'shiftkeys in'said basestructure, a pair of case shift mechanisms in said base structure respectively under control of saidcase shift keys, a shift-shaft mounted in saidbase'for oscillation about itsaxis,'a connection between one ofsaid case shift mechanisms and said shaft for oscillating'said shaft in one direction, a connection tbetween the'other'of said case shift mechanisms and said shaft for oscillating said shaftin'the other direction, 'a pair offlexible power transmitting tapes interconnecting said case shift-shaft andrsaid platen support'for'respectively transmitting motion thereto in opposite directions, and a'two part pivoted lever'in contact with each of saidtapes for maintaining a uniform amount of tension thereon as said carriage reciprocates' transversely 'of said base structure, each of said levers having one end pivoted on said. base structure and the other end thereof pivoted on saidcarriage.

References Cited in the file of this patent UNITED STATES PATENTS "1,627,390 Hokanson May 3, 1927 1,741,689 'Ely Dec. 31, 1929 2,171,703 -Kurowski Sept. 5, 1939 2,264,206 Helmond Nov. 25, 1941 

